307 tapping thoughts?

[Bonnewagon]

Definitely a real headscratcher! Early EGR valves were simple and could be checked by applying vacuum. Later EGR valves are the "backpressure" type that don't actuate unless there is exhaust backpressure present to close an internal valve. Simply applying vacuum won't actuate it. Best you can do is physically push the diaphragm in, if possible. Actuating a good valve will cause an idling motor to run rough or die. Are there any other EGR controls that may be malfunctioning, like a TVV or TVS? As for only #8 making noise, while that might indicate a bad bearing, it would get louder as rpm's increased, which your's doesn't. Weird.

 

[hurst1979olds]

I have had an engine that a customer overheated and it had a noise in it, that did not go away when it was hot. It had a piston slap. I was able to diagnose it by shorting out the cylinders. With a piston slap the noise will be less to not there when shorted out. If you got good oil pressure then its not a rod.

 

[SilvrPegasus47]

Have the same problem with my 86 Olds 442 62,000 org miles and the motor taps. I had all 16 lifters replaced than it stopped 3 months later back. when the engine heats up it gets louder. But oil pressure never drops. Some Olds mechanic told me it was a wrist pin. I give up ,,,,,Im putting in a 350 olds these cars should have came with them. So I have a 307 for sale Vin 9 its still in the car if anyone is intrested

How much are you asking on that motor?

 

[techg8]

Have the same problem with my 86 Olds 442 62,000 org miles and the motor taps. I had all 16 lifters replaced than it stopped 3 months later back. when the engine heats up it gets louder. But oil pressure never drops. Some Olds mechanic told me it was a wrist pin. I give up ,,,,,Im putting in a 350 olds these cars should have came with them. So I have a 307 for sale Vin 9 its still in the car if anyone is intrested

How much are you asking on that motor?

Do me a favor and dont hijack my thread fellas.

you can pm each other or start a forsale thread easily.

Thanks for your understanding, and good luck working out a deal.

 

[techg8]

Definitely a real headscratcher! Early EGR valves were simple and could be checked by applying vacuum. Later EGR valves are the "backpressure" type that don't actuate unless there is exhaust backpressure present to close an internal valve. Simply applying vacuum won't actuate it. Best you can do is physically push the diaphragm in, if possible. Actuating a good valve will cause an idling motor to run rough or die. Are there any other EGR controls that may be malfunctioning, like a TVV or TVS? As for only #8 making noise, while that might indicate a bad bearing, it would get louder as rpm's increased, which your's doesn't. Weird.

I put the EGR valve back on for backpressure and used a manifold vacuum line to check actuation of the valve.

I could feel it "flutter" a little under revs but it wasnt really opening far. so some egr was getting thru but not a lot I think.

I then revved up manually to get the knocking started, and used my finger to open the EGR further.

It immediately quieted the knocking.

So I think the EGR valve may not be good. I am going to replace it and see what gives.

It was encouraging that the knock went away with additional EGR. In my opinion that indicates it likely is not something mechanical like piston slap etc.

will advise....

 

[techg8]

meh

no such luck. replaced the EGR valve and it still knocks. and manually opening the egr doesnt eliminate the knock.

I ran a good bit of seafoam thru it again hoping against hope that it will rid cyl 8 of something that makes it knock.

Otherwise I am leaning toward wrist pin or piston slap at this time.....though a wrist pin would get louder with load.

someone tell me its something else....

I have a friend with a bore-o-scope. Maybe I will borrow it and pull the 8 plug and see what gives inside the combustion chamber.

 

[techg8]

found a youtube video of a 307 doing something very similar to mine.

My rockers are much quieter than this 307s but the knock is very similar.

again this is not my engine but has similar symptom.

http://www.youtube.com/watch?v=QtKOo1pn7ek

I should take a video of mine......

 

[Bonnewagon]

That sounds internal. Definitely NOT the EGR causing pinging.

 

[techg8]

well I went out to start the car and get a video of the tapping/knocking......and it wouldnt start.

went to pull the #1 plug wire to check for spark......and pulled the wire off the crimped end....

when it rains it pours i guess...or for today... when it snows it pours.

Anyhow I recrimped the #1 wire and checked for spark - none.

I put everything back and am going to wait for a warm day to take a peek at it.

 

[techg8]

it stopped snowing so I too a look at the distributor. The coil had gone bad evidently. replaced it with one out of a spare HEI and its running again.

Still has the knock. I took a video and am trying to post it on youtube. which is giving me trouble uploading.......when i get it done I will post the link.